Method and apparatus for making bags



Apri123, 1968 T. E. PIAZZE 3,379,101

METHOD AND APPARATUS FOR MAKING BAGS Filed March 4, 1966 2 Sheets-Sheet 1 April 23, 1968 T. E. PIAZZE 9,

METHOD AND APPARATUS FOR MAKING BAGS Filed March 4, 1966 2 Sheets-Sheet 2 United States Patent 3,379,101 METHOD AND APPARATUS FOR MAKING BAGS Thomas E. Piazze, Mount Vernon, Ohio, assignor to Continental Can Company, Inc., New York, N.Y., a corporation of New York Filed Mar. 4, 1966, Ser. No. 531,903 11 Claims. (Cl. 938) This invention relates to the manufacture of bags and is more particularly concerned with improvements in a method and apparatus for forming bags of flexible plastic sheet material.

It is a general object of the invention to provide an improved method and apparatus for forming bags from flexible plastic sheet material wherein the material in flattened tubular form is cut into bag forming lengths or sections and each section is closed at one end by sealing and folding operations so as to provide a square bottom formation when the bag is set up for use.

It is a more specific object of the invention to provide a bag forming method and apparatus wherein a Web of flexible bag making material is initially folded longitudinally and sealed to form a flattened tube, the tube is then divided into a series of bag forming lengths each with one end closed, each bag forming length is opened up on a mandrel and the closed end is re-formed and provided with additional seals which result in a square or rectangular bottom construction when the bag is set up for filling with a product.

It is still another object of the invention to provide a method and apparatus for fabricating bags by forming flexible sheet material into tube-like sections with one end of each section flattened and closed by a transverse seam, opening up each tubular section so as to provide a bottom forming portion at the closed end of the tubular section having triangular end portions extending outwardly of oppositely disposed, triangular side wall sections, forming seals across the triangular end portions at the bottom forming edges of the side wall sections so as to provide a diamond shaped end wall formation and removing that part of each of the triangular portions which is outside of the sealed area.

It is a further object of the invention to provide a method of fabricating a bag which comprises transversely sealing one end of a section of flexible tubular material, opening up the tubular section on triangular shaped plate mandrels so as to cause the end with the transverse seal to open out into a transverse plane with triangular end portions extending in said plane and outwardly of oppositely disposed side wall sections, sealing across the inside edges of the triangular portions resulting in the formation of a diamond-shaped end wall with triangularshaped waste portions at opposite ends thereof, removing the Waste portions which are outside of the sealed edges, collapsing the mandrel and folding the diamondshaped end wall upon itself while flattening the side wall of the bag.

These and other objects and advantages of the invention will be apparent from a consideration of the method and apparatus for forming the bags which are shown by way of illustration in the accompanying drawings wherein:

FIGURE 1 is a plan view, largely schematic, illustrating an improved apparatus for forming bags in accordance with the method which constitutes the present in- Vention;

FIGURE 2 is a view showing in side elevation the apparatus illustrated in FIGURE 1;

FIGURE 3 is a view taken on the line indicated at 33 in FIGURE 2, to an enlarged scale and with portions broken away or omitted;

3,379,101 Patented Apr. 23, 1968 FIGURES 4, 5, 6, 7 and 8 are views taken on the lines 44, 55, 6-6, 77 and 8-8 of FIGURE 2, to an enlarged scale and showing in each instance the condition of the closed en dof the bag which is at the outer end of the mandrel;

FIGURE 9 is a fragmentary side elevation of one of the mandrel assemblies; and

FIGURES 10 is a plan view with portions broken away of the finished bag in flattened condition as it is delivered from the machine.

In the method and apparatus which is illustrated in the drawings and which embodies the principal features of the present invention, a web W of a suitable bag forming material, such as, a relatively thin film of polyethylene plastic is employed. The plastic web W is delivered from a supply roll or other source, and is formed into a tube T on a folding horn of conventional construction, as indicated at 12, and a longitudinal seam 13 is formed in the tube by joining overlapped marginal edge portions of the web W. The sealing of the overlapped margins may be accomplished, as shown, by a hot wire back seam sealing device 14 operating against the flat end extension 15 of the forming horn member 12. Alternatively, the seal may be formed by a heat sealing roller operating against an internal sealing plate with a suitable backing roller. The flattened tube T which is thus formed is divided into bag forming lengths by sealing transversely at longitudinally spaced intervals, the seals being applied by intermittently operating, reciprocating, top and bottom sealing irons 17 and 18 which are adjustable longitudinally of the path of the tube T so as to permit variation in the length of the bag forming tube sections or lengths L. The tube is advanced by continuously driven feed rolls 19 to a pair of intermittently driven feed rolls 20 with an interposed dancing roll 21. The feed rolls 20 advance the tube relative to the sealing irons 17, 18 and a co-operating set of intermittently driven feed rolls 22 is arranged in longitudinally spaced relation to the feed rolls 20. Cutting bar or shear members 23 and 23' are arranged in advance of the feed rolls 20, which sever the tube adjacent the transverse seal 16 and divide the same into separate bag forming sections or lengths L of equal size.

Each successive bag forming length or section L is then advanced by co-operating top and bottom pick-up rolls 24 and 24' in timed relation to the rotation of a mandrel carrying turret 25 and telescoped onto one of a plurality of collapsed mandrels 26 which are carried in peripherally spaced relation on the turret wheel 25. Each bag section L is advanced from the pick-up or timing rolls 24 and 24' on a pair of belts 27, 27' which are supported at one end on the bottom timing rolls 24' and at the other end on support rolls 28 and 28 arranged so as to provide horizontally disposed top, belt runs on which the tube lengths L are held by longitudinally spaced holddown rollers 29. The supporting rolls 28 and 28' at the leading end of the belts 27 nad 27 are arranged on opposite sides of the path of the mandrel assemblies 26 and the turret 25 is operated intermittently to position successive mandrel assemblies 26 in the plane of the top run of the belts 27 and 27' so as to permit the tube lengths L to be telescoped over successive collapsed mandrel assemblies 26. The leading end or mouth of each tube section L is opened up so that it will telescope over the collapsed mandrel 26 by a pair of rotatably mounted suction arms 30 and 30' which are opera-ted to grip opposite wall portions of each tube section adjacent the leading end and move apart a predetermined distance suflicient to receive the mandrel in the thus opened end of the tube section and which may also advance with the tube section to help feed the same onto the mandrel.

Each mandrel assembly 26 comprises a pair of fiat plates 31 and 31 which are of generally triangular shape and pivoted at the base or inner end to the turret so that the outer ends may be opened up or moved apart after the tube section L is telescoped thereon. The two plates 31 and 31' of each mandrel assembly 26 may be mounted on the side plates 32, 32' of the turret 25 by securing flanged inner ends thereof to cross rods 33 and 33 which are journaled in the side plates 32 and 32' and have interengaging gears 34 for operating the same in unison. The one cross rod 33 carries a cam roller arm 35 with a cam roller 35 on the free end which is adapted to engage a track forming edge on a plate or ring cam 36 which is fixed relative to the turret 25 so that it remains stationary while the turret rotates. The cam roller 35 is held against the cam track by a spring 37 so that the cam 36 controls the opening and closing of each pair of plates 31 and 31 as the turret 25 rotates. The plates 31 and 31' are out off at the outer apex so as to form a short end edge 38 extending transversely of the radial axis of the plates.

The turret 25 rotates in a clockwise direction, as viewed in FIGURE 2, and each mandrel assembly 26 receives a bag forming tube length L at station A, While the plates 31 and 31' are in collapsed or closed condition. As the turret advances the mandrel assembly 26 to the next station B the plates 31 and 31' are opened up or swung apart at the outer ends so as to spread the portions of the trailing or sealed end of the bag forming section L which assume the rectangular shape illustrated in FIGURE 4 with the seal 16 extending transversely of the face of the collapsed mandrel and in approximately the same plane as the radially extending axis of the plates. At the next station C reciprocably mounted sealing elements, indicated at 40, engage triangular end portions 41, 41' and form cross seals 42 and 42 which are substantially parallel with the faces of the plates 31 and 31'. The sealing de vices are adjustably mounted so as to accommodate different size bag operations. A knife assembly or other cutting device 43 is mounted on each side of the path of the mandrels at station E for removing the part of each of the triangular wall portions 41 and 41 which is outside of the cross seals 42 and 42, leaving the closed end of the bag section with a diamond shape as shown in FIGURE 7. The waste portions 41 and 41' may be removed through a suction line or otherwise disposed of. At station F the now completely closed end of each bag section is folded into fiat condition as shown in FIGURE 8 with the projecting end folds extending beyond the outer end of the mandrel 26 and positioned to be received between the bag stripping rolls 45, 45' at station G. The stripping rolls 45, 45 are mounted on a supporting frame or pair of arms 46 extending from a fixed pivot 47 and arranged to be reciprocated in a short vertical path beneath the outer end of the mandrel. The stripping rolls 45 and 45 are connected by a chain drive, indicated at 48, with a driven shaft mounted on the pivot axis 47. The mandrel 26 is, of course, collapsed to permit the bag to be removed by the rolls 45, 45. A belt conveyor 50 disposed beneath station G delivers the completed bags to a stack 51 or a suitable storage receptacle.

The bags, when completed on the turret 25, may be delivered, if desired, directly to a bag filling and closing machine, for example, a machine of the type disclosed in my Patent No. 2,976,660 with the bags being ejected from the mandrels 26 at station E. The mandrels 26 may be collapsed to release the bags and an air blast employed to eject the bags and deliver them to a transfer device for seating in successive pockets in the supporting conveyor on the bag filling and closing machine.

While particular materials and specific structural details are referred to in describing the method and apparatus illustrated, it will be understood that other materials and equivalent structural details may be employed within the spirit of the invention.

I claim:

1. A method of fabricating bags which comprises transversely sealing at predetermined intervals a flattened tube of flexible bag forming material, severing the tube adjacent the successive transverse seals to divide the tube into bag forming sections of uniform length, telescoping the open end of each bag section over a collapsed plate mandrel, opening up the mandrel so as to cause the end with the transverse seal to open out into a transverse plane with triangular end portions extending in said plane and out- Wardly of oppositely disposed side wall sections which are generally triangular and in planes converging in the direction of the open end of the bag section, sealing across the inside edges of the triangular end portions resulting in the formation of a diamond-shaped end wall with triangular shaped waste portions outside the sealed edges, collapsing the mandrel and flattening the completed bag for removal from the mandrel.

2. A method of fabricating bags as recited in claim 1, and flattening the finished bag when the mandrel is collapsed with the diamond-shaped transverse end wall folded upon itself and into the plane of the body of the bag.

3. A method of fabricating bags as recited in claim 1, and separating the triangular shaped waste portions outside of the sealed edges from the diamond-shaped end wall and discarding said waste portions.

4. A method of fabricating bags as recited in claim 3 and flattening the body of the finished bag when the mandrel is collapsed, and folding the diamond-shaped end wall along a center line thereof and in the direction outwardly of the free end of the mandrel so that said end Wall is fiattened into the plane of the body of the bag.

5. A method of fabricating bags which comprises folding a continuous web of bag forming film into a tube and longitudinally sealing the same, transversely sealing the tube at predetermined intervals, severing the tube adjacent the successive transverse seals to divide the tube into bag forming sections of uniform length, telescoping the open ends of the bag sections over a succession of collapsed, triangular plate mandrels, opening up each mandrel so as to cause the end of the bag section with the transverse seal to open out into a transverse plane with triangular end portions extending in said plane and outwardly of oppositely disposed side walls which are generally triangular and disposed in planes converging in the direction of the open end of the bag section, sealing across the inside edges of the triangular end portions resulting in the formation of a diamond-shaped end wall with triangular-shaped Waste portions outside the sealed edges, severing the material outside of the sealed edges and removing the triangular waste portions and collapsing the mandrel to permit the completed bag to be removed from the mandrel.

6. Apparatus for fabricating bags from flexible film material comprising means for advancing a continuous tube of the material, means for transversely sealing and severing the tube at predetermined intervals so as to divide the tube into successive bag forming sections of uniform length, a turret having peripheral spaced, collapsible mandrel assemblies each adapted to be positioned at a station for receiving successive bag sections in telescoped relation thereon, each mandrel assembly comprising a pair of triangular shaped, flat plates hingedly mounted on the turret for swinging movement on axes extending parallel with the axis of rotation of the supporting turret so that when opened up the outer ends of the plates are swung apart and portions at the sealed end of the bag section which is thereon are disposed in a transverse plane at the end of the mandrel assembly, means for sealing said end portions along spaced parallel edge forming lines, which extend diagonally across opposite corners thereof, means for severing waste forming triangular portions outside of said edge forming lines, and means for swinging said mandrel plates between a collapsed position for receiving the bag section and an opened up position for expanding the bag section so that oppositely disposed side wall portions assume a triangular shape and the sealed end portion is disposed in a transverse plane.

7. A machine for fabricating bags from flexible film material comprising means for forming the material into a tube, means for advancing the tube in a predetermined path, means for transversely sealing and severing the tube at longitudinally spaced intervals so as to divide the tube into bag forming sections of uniform length, a turret having radially extending, peripheral spaced, collapsible mandrel assemblies, means to rotate the turret so as to position successive mandrel assemblies at a station for receiving the bag sections, means for positioning the bag sections in telescoped relation on collapsed mandrel assemblies at said station, each mandrel assembly comprising a pair of triangular shaped, flat plates, each pair of plates being hingedly mounted on the turret at their base forming edges for swinging movement on axes extending parallel with the axis of rotation of the supporting turret so that when swung to open position the outer ends of the plates are moved apart and portions of the bag section at the sealed end are opened out into a transverse plane at the end of the mandrel assembly, means for sealing across said opened out end, said sealing means engaging the material along spaced parallel edge forming lines which extend diagonally across opposite corners of said sealed end, means for severing waste forming triangular portions outside of said edge forming seal lines, means for removing said triangular Waste portions, and means for swinging said mandrel plates between a closed position for receiving the bag section and an open position for expanding the bag section so that oppositely disposed side Wall portions are engaged by outside faces of the mandrel plates and the sealed end portion is disposed in a transverse plane.

8. A machine as recited in claim 7, and said mandrel plates being mounted on closely spaced, parallel shafts, an arm extending radially of the axis of one of said shafts, a cam roller on said arm and a cam member mounted in fixed relation to said turret for engaging said cam roller and controlling the opening and closing of the mandrel plates.

9. A machine as recited in claim 7, and said sealing and severing means being arranged at Work stations which are peripherally spaced about said turret.

it). A machine as recited in claim 7, and the means for positioning the bag sections on the mandrels comprising a belt conveyor and associated means for opening the leading end of each successive bag section as it is advanced to a mandrel assembly on the turret.

11. A machine as recited in claim 7, and the means for positioning the bag sections on the mandrels comprising a pair of spaced conveyor belts and associated vacuum gripper means for engaging the opposite faces of each successive bag section at the leading end thereof and for moving the bag Wall sections apart to receive the collapsed mandrel.

References Cited UNITED STATES PATENTS BERNARD STICKNEY, Primary Examiner. 

1. A METHOD OF FABRICATING BAGS WHICH COMPRISES TRANSVERSELY SEALING AT PREDETERMINED INTERVALS A FLATTENED TUBE OF FLEXIBLE BAG FORMING MATERIAL, SEVERING THE TUBE ADJACENT THE SUCCESSIVE TRANSVERSE SEALS TO DIVIDE THE TUBE INTO BAG FORMING SECTIONS OF UNIFORM LENGTH, TELESCOPING THE OPEN END OF EACH BAG SECTION OVER A COLLAPSED PLATE MANDREL, OPENING UP THE MANDREL SO AS TO CAUSE THE END WITH THE TRANSVERSE SEAL TO OPEN OUT INTO A TRANSVERSE PLANE WITH TRIANGULAR END PORTIONS EXTENDING IN SAID PLANE AND OUTWARDLY OF OPPOSITELY DISPOSED SIDE WALL SECTIONS WHICH ARE GENERALLY TRIANGULAR AND IN PLANES CONVERGING IN THE DIRECTION OF THE OPEN END OF THE BAG SECTION, SEALING ACROSS THE INSIDE EDGES OF THE TRIANGULAR END PORTIONS RESULTING IN THE FORMATION OF A DIAMOND-SHAPED END WALL WITH TRIANGULAR SHAPED WASTE PORTIONS OUTSIDE THE SEALED EDGES, COLLAPSING THE MANDREL AND FLATTENING THE COMPLETED BAG FOR REMOVAL FROM THE MANDREL. 